1. Field of the Invention
This invention relates to a removable strain gauge fixture, and a method for measuring the accumulated strain in a material, such as the rail of a railroad track.
2. Description of the Prior Art
Strain gauges for measuring strain in structural components are known in the prior art. Typically, such strain gauges generally comprise a strain gauge carrier having an electronic strain sensor mounted thereon. In use, the strain gauge carrier is usually welded or otherwise permanently affixed to the component being measured. A first strain reading is taken when the component is in a strain-free state. Next, the component is subjected to strain, and a second strain reading is taken. The strain, and therefore the stress, is computed by subtracting the values of the two readings, and multiplying the result by an appropriate constant.
While prior art strain gauges are capable of rendering accurate strain measurements in certain applications, such gauges may provide unreliable and inaccurate results when used in a hostile environment over a long period of time. Specifically, such gauges have been known to fail a few years after being attached to a railroad rail, where weather and vibration take a daily toll on both the gauge carrier as well as the delicate electronic strain sensor. Such gauges are not designed to be removed from and reattached to their respective rails, and therefore must remain with the rail and its environment throughout the life of the test.
Clearly, a need exists for a strain gauge and a strain measurement method in which the gauge fixture is easily attachable and removable from the component being measured and hence capable of being stored in an ideal environment when not in use, and which is capable of transferring and measuring accumulated strain when attached onto the component. Ideally, such a strain gauge fixture should be simple and inexpensive to fabricate, and the method of using it should be easy to carry out and capable of rendering accurate, reliable strain measurements.